Vacuum oil quench furnace

ABSTRACT

A vacuum quenching apparatus comprises a vacuum chamber in which is mounted a heating furnace and a quenching tank. A dolly rides on rails from a position over the quenching tank to a position adjacent the furnace and is provided with parallel supporting arms which support a load therebetween and which extend into the furnace when the dolly is positioned adjacent thereto. The arms are counter-rotatable so as to release a load and permit the load to descend vertically downwardly either within the furnace or upon a hydraulic cylinder mounted within the quench tank. An end of the chamber is also displaceable, and the dolly moves outwardly with the displaceable end to permit loading or unloading.

waited States Patent Genrich [451 Aug.-l5, 1972 VACUUM OIL QUENCH FURNACE [72] Inventor: Kurt Genrich, Oak Park, Ill.

[73] Assignee: Sola Basic Industries, Inc., Milwaukee, Wis.

[22] Filed: Feb. 12, 1970 [21] Appl. No.: 10,923

[52] US. Cl. ..266/4 A, 148/153 [51] Int. Cl. ..C21d 1/66 158] Field of Search ..148/143, 144, 153; 266/4 R, 266/4 A, 4 B, 4 E, 4 F

156] References Cited UNITED STATES PATENTS 3,441,452 4/1969 Westeren ..148/143 3,025,044 3/1962 Giler ..266/4 R 2,458,084 1/1949 Lee ..266/4 B 1,888,960 11/1932 Talley ..266/4 R FOREIGN PATENTS OR APPLICATIONS 987,910 8/1951 France ..266/4 R Primary 'ExaminerGerald' A. Dost At!0rney---Smythe & Moore 1 5 7 1 ABSTRACT A vacuum quenching apparatus comprises a vacuum chamber in which is mounted a heating furnace and a quenching tank. A dolly rides on rails from a position over the quenching tank to a position adjacent the furnace and is provided with parallel supporting arms which support a load therebetween and which extend into the furnace when the dolly is positioned adjacent thereto. The arms are counter-rotatable so as to release a load and permit the load to descend vertically downwardly either within the furnace or upon a hydraulic cylinder mounted within the quench tank. An end of the chamber is also displaceable, and the dolly moves outwardly with the displaceable end to permit loading or unloading.

6 Claims, 5 Drawing Figures PATENTEDAUB l 5 I972 SHLET [1F 4 ATTORNEY VACUUM OIL QUENCI-I FURNACE The invention relates to integral vacuum quenching apparatus for heat treating of metals.

in a heat-treating quenching process, a hot load is transferred above and lowered into the quench liquid at rather high speeds in order that the temperature of the load decreases as little as possible and also to move the hot load through the surface of the quenching oil as fast as possible in order not to heat the oil over a localized point to such an extent that the oil would either ignite or evaporate. The apparatus for carrying out such a heat-treating quench process generally comprises a heating furnace and an oil-filled quench tank. The quench tank is usually kept as cool as possible and is therefore separated from the heating furnace by a heat shield or even by a vacuum door. The resulting structure is unduly complicated and requires considerable skill in operation in order to carry out properly aquenching process.

One of the objects of the present invention is to provide an improved integral vacuum quenching apparatus.

Another of the objects of the present invention is to provide an improved transfer mechanism for a vacuum quenching apparatus.

Another of the objects of the present invention is to facilitate the transfer of the load in and out of the heating furnace of a vacuum chamber and positioning the load over the quenching oil for immersion therein.

According to one aspect of the present invention, a vacuum quenching apparatus may be provided with a chamber which is evacuable to a sub-atmospheric pressure, the chamber having a heating furnace therein. A quenching tank is also positioned within the vacuum chamber and mounted lower than the heating furnace. A transfer mechanism is movable into and out of the furnace to a position over the quenching tank. The transfer mechanism includes means for supporting a load and for releasing the load vertically downwardly. Within the quenching tank are provided hydraulic cylinder means to receive a load released from the transfer mechanism when the transfer mechanism is positioned over the quenching tank. The transfer mechanism may comprise rail means within the chamber extending over the quenching tank and underneath the furnace with there being a dolly movably mounted on the rail means. The dolly may comprise a pair of parallel supporting arms which extend into the furnace when the dolly is moved on the rail means underneath the furnace. The arms have inwardly directed ledges upon which the load is actually supported, and the arms may be counter-rotated so that the ledges are pivoted from under a load to permit the load to be released vertically downwardly.

Other objects, advantages and features of the present invention will become apparent from the accompanying description and drawings, which are merely exemplary.

In the drawings:

FIG. 1 is a vertical longitudinal sectional view of a vacuum quenching apparatus according to the present invention;

FIG. 2 is a sectional view taken along the line 22 of FIG. 1;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 1;

FIG. 4 is a portion of a view similar to that of FIG. I but showing an end plate of the chamber in an open position; and

FIG. 5 is a top plan view of the apparatus as shown in FIG. 4.

Proceeding next to the drawings wherein like reference symbols indicate the same parts throughout the various views, a specific embodiment of the present invention will be described in detail.

As may be seen in FIG. 1, the vacuum quenching apparatus of the present invention comprises a chamber means indicated generally at 10 which can be evacuated to establish a vacuum therein. The chamber comprises a horizontally disposed cylinder 11 surrounded by a water jacket 12 and having a fixed end 13 and a removable end 14. A cylindrical quenching tank 15 is connected to the lowermost portion of the cylinder 11 to communicate therewith.

The heating furnace 16, which may be electric, is positioned within the cylindrical portion 11 adjacent the fixed end 13. The furnace 16 is provided with a door 17 which is lifted outwardly and upwardly by a hydraulic piston arrangement 18 mounted within an enclosure 19 projecting above the upper surface of the cylinder. Suitable linkage 20 connects the door to the hydraulic piston. Within the furnace 16 are positioned a plurality of vertical supporting members 21 upon which a load is to be positioned.

The quenching tank 15 is provided with watercooled cylindrical walls 22 and 23 to dissipate the heat between quenches. Openings 24 are provided under the bottom of the wall 22. These cylindrical walls provide a channeling effect to the quench oil so that percent of the flow is flushed through the work. The quenching oil is circulated in the directions indicated by the arrows by a motor-driven agitator 26.

Mounted within the innermost wall 22 in the quenching tank 15 is a hydraulic cylinder 27 of the single-acting ram type which is totally submerged in the quenching oil and which may be raised out of the oil to receive or deposit the load. The hydraulic cylinder 27 may be of the telescoping type in order not to occupy excessive space within the quenching tank. The upper end of hydraulic cylinder 27 is provided with a supporting platform 27A upon which a load 28 may be positioned. Hydraulic cylinder 27 may be operated with the same oil as used for quenching or with oil emulsions of the nature used for quenching so that any leaks from the cylinder would not contaminate the quench bath.

The mechanism for transferring a load, such as indicated at 28, from the furnace 16 to the quenching tank 15 comprises a dolly 29 mounted on wheels 30 upon a pair of parallel rails 31 which extend over the quenching tank 15 and underneath the furnace 16 as shown in FIG. 1. The rails are broken at 31A so that the left portion can be moved with end 14 when the end is opening as can be seen in FIG. 4.

At one end of the dolly is a vertical supporting upright 32 from which extend two spaced parallel supporting arms 33 which, as may be seen in FIG. 2, are spaced apart a distance slightly greater than the width of the load 28. The supporting arms are rotatably mounted in bearing blocks 34 and on their inner faces are provided with inwardly extending ledges 35 upon which the load 28 actually rests as shown in FIG. 2.

A lever arm 36 extends outwardly from each of the supporting arms 33 and is pivotally connected at 37 to a piston rod 38 of a hydraulic cylinder 39 having its upper end connected at 40 on the upright structure 32. Actuation of the hydraulic cylinder 39 to retract piston rod 38 will rotate the supporting arm 33 approximately 90 and cause the supporting ledges 35 to be pivoted to the dashed line position indicated at 35A.

Dolly 29 moves horizontally upon the rails 31 by means of an endless chain 41 to which it is connected. Chain 41 will pull the dolly in either direction upon its wheels. This chain 41 is driven by suitable shaftmounted sprocket gears.

The removable end 14 of the cylinder is mounted by means of a suitable supporting structure indicated at 42 to wheels 43 which roll upon parallel rails 44 secured to the outer surface of the cylinder 11 as may be seen in FIGS. 4 and 5. Thus, the removable end 14 may be displaced to the position as shown in FIGS. 4 and together with the dolly 29 to provide access to the dolly and facilitate the loading and unloading thereof.

In carrying out a quenching process with the apparatus of the present invention, the vacuum pump is started to begin evacuation of the chamber to the desired vacuum or pressure and the several hydraulic pump motors also are started. With removable end 14 of the chamber in the position as shown in FIGS. 4 and 5, a load 28 is placed upon the dolly. Removable cylinder end 14 is then closed to move the work load 28 into the cooling section as shown in FIG. 1. Upon opening of a vacuum valve, evacuation of the chamber begins. The furnace door 17 is opened and the work load 28 introduced into the furnace by moving the dolly into a position underneath the furnace. When the dolly is moved in this position, the supporting arms will protrude into the chamber and are rotated to permit the work load to be positioned upon the supports 21 within the furnace.

Upon completion of the heat cycle, the quench oil agitator is started. When the correct oil temperature is attained, the door of the heating furnace is opened and the work removed therefrom by the transfer mechanism. When the work is loaded on the supporting arms, the dolly is moved rearwardly to the position as shown in FIG. 1, and the hydraulic quench cylinder 27 is actuated so that its support platform 27A is in position to receive the work load 28. The supporting arms of the dolly are again counter-rotated to release the load upon the support platform. The cylinder will then lower the work into the oil quench bath.

Upon completion of the quenching cycle, the quench cylinder will raise the work onto the transfer mechanism and then air is admitted into the chamber and the removable end 14 is opened to withdraw the work from the chamber.

The apparatus may also be used for a gas quenching process. In such a process, the vacuum valve is closed, and a back-fill valve is opened to admit a suitable gas into the chamber. A circulating fan 45 located within the chamber is driven by electric motor 46 to circulate the gas throughout the chamber. When the work load is removed from the surface 16 at the end of the heating cycle, the dolly and the load are positioned as shown in FIG. 1 so that the work load may be subjected to the gas quenching.

It will be apparent that a vacuum oil quenching apparatus employing a transfer mechanism according to the present invention has several advantages. The work load supports in the heating chamber may be constructed in a manner of simple stationary pier supports without the necessity for providing any lifting, lowering or sidewise motions with respect to the transfer of work into and out of the heating furnace. The transfer of the work load to and from the transfer mechanism does not depend on any sliding, skidding, rolling or other movements causing friction which would be detrimental in a high temperature environment. Further, the dolly remains over the oil quenching tank to transfer and receive the load from the quenching elevator.

It will be understood that various details of construction and arrangement of parts may be made without departing from the spirit of the invention except as defined in the appended claims.

I claim:

1. In an integral vacuum heat-treating and quenching apparatus, chamber means evacuable to sub-atmospheric pressure, a heating furnace within said chamber means, a quenching tank within said chamber means and lower than said heating furnace, a horizontally movable transfer mechanism movable into and out of said furnace and to a position over said quenching tank, means mounted on said horizontally movable transfer mechanism for supporting a load and operable for releasing a load supported thereon vertically downwardly, and vertically movable transfer means within said quenching tank movable upwardly to receive a load when released from said transfer mechanism when the transfer mechanism is in position over the quenching tank and .moving the load downwardly without the horizontally movable transfer means and into the quenching tank and for moving it upwardly after quenching where it can again be transferred onto said horizontally movable transfer mechanism.

2. In an integral vacuum heat-treating and quenching apparatus, chamber means mospheric pressure, a heating furnace within said chamber means, a quenching tank within said chamber means and lower than said heating furnace, a horizontally movable transfer mechanism movable into and out of said furnace and to a position over said quenching tank, means on said horizontally movable transfer mechanism for supporting a load and for releasing a load vertically downwardly, said transfer mechanism including rail means within said chamber extending over said quenching tank and underneath said furnace, and a dolly movably mounted on said rail means, and vertically movable transfer means within said quenching tank movable upwardly to receive a load when released from said transfer mechanism when the transfer mechanism is in position over the quenching tank and moving the load downwardly into the quenching tank and for moving it upwardly after quenching.

3. In an apparatus as claimed in claim 2 wherein said dolly comprises a pair of parallel supporting arms positioned to extend into said furnace when the dolly is moved on said rail means underneath the furnace.

4. In an apparatus as claimed in claim 2 wherein said arms extend parallel to said rail means and are spaced evacuable to sub-attransfer mechanism comprises rail means within said chamber extending over said quenching tank and underneath said furnace, a dolly movably mounted on said rail means, said rails being slidably mounted within said chamber and movable with said displaceable end member so that the dolly thereon may be withdrawn from the chamber in a loading and unloading position. 

1. In an integral vacuum heat-treatiNg and quenching apparatus, chamber means evacuable to sub-atmospheric pressure, a heating furnace within said chamber means, a quenching tank within said chamber means and lower than said heating furnace, a horizontally movable transfer mechanism movable into and out of said furnace and to a position over said quenching tank, means mounted on said horizontally movable transfer mechanism for supporting a load and operable for releasing a load supported thereon vertically downwardly, and vertically movable transfer means within said quenching tank movable upwardly to receive a load when released from said transfer mechanism when the transfer mechanism is in position over the quenching tank and moving the load downwardly without the horizontally movable transfer means and into the quenching tank and for moving it upwardly after quenching where it can again be transferred onto said horizontally movable transfer mechanism.
 2. In an integral vacuum heat-treating and quenching apparatus, chamber means evacuable to sub-atmospheric pressure, a heating furnace within said chamber means, a quenching tank within said chamber means and lower than said heating furnace, a horizontally movable transfer mechanism movable into and out of said furnace and to a position over said quenching tank, means on said horizontally movable transfer mechanism for supporting a load and for releasing a load vertically downwardly, said transfer mechanism including rail means within said chamber extending over said quenching tank and underneath said furnace, and a dolly movably mounted on said rail means, and vertically movable transfer means within said quenching tank movable upwardly to receive a load when released from said transfer mechanism when the transfer mechanism is in position over the quenching tank and moving the load downwardly into the quenching tank and for moving it upwardly after quenching.
 3. In an apparatus as claimed in claim 2 wherein said dolly comprises a pair of parallel supporting arms positioned to extend into said furnace when the dolly is moved on said rail means underneath the furnace.
 4. In an apparatus as claimed in claim 2 wherein said arms extend parallel to said rail means and are spaced apart greater than the width of a load, and means on said arms for supporting a load.
 5. In an apparatus as claimed in claim 2 wherein said supporting means comprise inwardly extending ledges, and means for counter-rotating said arms to pivot said ledges from under a load so that the load is released downwardly between said supporting arms.
 6. In an apparatus as claimed in claim 2 wherein said transfer mechanism comprises rail means within said chamber extending over said quenching tank and underneath said furnace, a dolly movably mounted on said rail means, said rails being slidably mounted within said chamber and movable with said displaceable end member so that the dolly thereon may be withdrawn from the chamber in a loading and unloading position. 